I’ve seen some tests of AA batteries where the capacity variation in a 10 cell pack could be as much as 70% difference between the best and the worst

What are the capacity tolerances on a typical battery anyway? are they ever specified. I believe output voltage and internal resistance are monitored at manufacturing, but how about the capacity the battery can deliver when its energy is drawn over hours/days/months or even years.

Though I’m not saying this explains the test results we seen so far.

Nope, I don't think it's that which is causing the crappy results, I just want to be sure that Batteroo can't come back and claim it is.

Capacity is temperature and load dependant so we need to know current drawn but the tests we have so far are not indicative of a product that works as advertised.

Go figure, who could have predicted that...

The only way to be conclusive is to amass a large statistically significant number of test results so that faulty or low capacity cells can be weeded out.

Anyone care to guess why the result is so bad? Simply looking at the efficiency does not explain it.Frank, did you measure the current consumption of the train? Maybe I missed it...

That's easy : current in the load : 250 mA at 1.5 V and 210 mA at 1 V.

let's say the converter has 88% efficiency.

Iout =250mA @ Vout =1,5V at the load means you have : Iin=Iout*Vout/Vin /Eff = .25*1,5/1/0,88 = 420mASo you take up much more current, which already lowers the time nearly half.Also, higher current means lower capacity on the battery itself :http://data.energizer.com/PDFs/E92.pdf --> on the bar graphic you see the battery capacity going down with increased current, perhaps 30%

So, all in all, about half the run time with a simple unregulated load like a motor or a non active light is expected.Batteriser is a total and utter fail.

Another way to look at the results of this excellent train test is by means of WORK DONE, rather than time of operation.So, we can view one complete lap or circuit of the track as being ONE unit of work.Fresh Bare cell: 613 laps.Fresh cell with Batteroo: 290 laps.The cell from test one, after being allowed an hour to recover, went on to do another 17 laps with the batteroo on. (I contend that the extra 17 laps were from the cell's natural recovery over one hour rather than any gain from the batteroo sleeve, but hey, without this having been tested in this instance, we'll give batteroo the benefit of the doubt for now.)

Interestingly, regarding the RATE of work done, in the first 58 minutes and 35 seconds, the bare cell test completed 314 laps, while the batteroo'd train completed its 290 laps. So it didn't even increase the output.Batteroo decreased the RATE of operation, the TIME PERIOD of operation, and the AMOUNT of work done. Fail on every measurable metric.

Err, well, I'm a nerd with a bit of time on my hands just at the moment and not enough sleep; so I used one of those clicker counter things, and just watched the video and clicked it each time the train completed a lap... Cheers though!

I don't think the minute weight of the sleeve would make a hell of a difference personally and if you were going to start factoring in those minuscule details then you may also want to consider that the moving parts of the train over time will probably free up with wear, I wouldn't worry about it at this point in time.

But I just did the train test with the sleeves again, this time checking the battery (was from the same pack of 4) and open loop voltage was 1.6 V. It is important to verify experiments. The Batteroo sleeve was the other one I have, so no faulty sleeve, no faulty battery. Time confirmed, 61 minutes this time.

We should include this measurement in the google doc too, just to keep the record.

Right, I guess it might be longer, too. But doesn't matter much, the interesting result is that the advantage is 3% instead of 300%.

I understand your argument. I am just curious whether that 3% extra turns out to be 0% in real term.

I think your test results should be indicative for all direct battery powered motorized devices and "toys", including the monkey ...

The other device types of interest are those with built-in DC-DC convertors and those with pulsed power consumption. The interest is mainly on checking all different predictions made throughout the 300+ pages.

Yes, I can almost guarantee that if the bare battery from the test with bare battery had been left to rest for an hour and reinserted again bare, without the batteroo, it would have run for at least as long, probably longer again than it did with the batteroo on. As a kid that was always my method with dead batteries, swap them back and forth giving them time to rest and the toy would always run again for a good while.You'd actually get a better increase in life from the "dead" battery by biting it hard and reinserting it than by putting a batteroo sleeve over it. Seriously.

I remember back when I was a kid, someone 'taught' me to put dead batteries out in bright daylight and they'll recover some 'energy' from the sun... I wonder if it's just the natural battery regeneration after all... Or maybe there's some truth in that the heat affects the chemical inside and it 'rearranges' to give higher recovered voltage or something?

At any rate, Is that train a pure resistive load ie. no regulation circuit at all? Also I agree, should do the test with the parameter of 'reinserting'

1) Test A without batteriser until train stops, keep battery aside and after a while (fixed time) and maybe some treatment(biting, sun-drying? ) reinsert and continue experiment2) Test B with batteriser, same as above, reinsert battery into batteriser and re-test.3) Test C without batteriser, reinsert into batteriser and re-test4) Test D with batteriser, reinsert without sleeve back and re-test

Frank: If you have a quality rechargeable Low Self Discharge Ni-MH AAA cell, like an eneloop lying around at your home, would it be possible to fully charge it and chuck it in the train and see how long it runs for (how long and how many laps)?

Just as a side comparison: (I would strongly advocate to potential buyers of batteroo, to instead take that money and invest it in a charger and a set of eneloops instead, which can last many hundreds of recharge cycles and are much more effective in most applications these days than Alkaline primaries. So they save money in the long run, they save the environment, and they work better. No brainer, especially as now with modern LSD types, self discharge isn't the problem it used to be with Ni-MH cells.)

Edit: Disclaimer: I have no affiliation with BRB - Big Rechargeable Battery!

eg. The train. If the train goes around the track faster with batteroo then they can declare it a "win" even if it only lasts half as long.

A better test might be "How many times does it go around the track?" and totally ignore the overall running time. It's less correct technically but I really think that "number of times around the track" would be a better set of numbers to show the public.

I believe we should consider any and all possible measuring sticks when doing these tests - and publish the lot of them. If one of those shows a benefit for Batteroo, then publish it. It's better to include all results so that the tester cannot be accused of being biased - and have that accusation proved by taking the tester's own data and using it against them. If there is one, you might find that the metric which shines in favour of Batteroo is measuring something that people don't really care about.

By publishing all the metrics, you get a much more persuasive message, especially when they all point in the same direction. Here's an example:

Another way to look at the results of this excellent train test is by means of WORK DONE, rather than time of operation.So, we can view one complete lap or circuit of the track as being ONE unit of work.Fresh Bare cell: 613 laps.Fresh cell with Batteroo: 290 laps.The cell from test one, after being allowed an hour to recover, went on to do another 17 laps with the batteroo on. (I contend that the extra 17 laps were from the cell's natural recovery over one hour rather than any gain from the batteroo sleeve, but hey, without this having been tested in this instance, we'll give batteroo the benefit of the doubt for now.)

Interestingly, regarding the RATE of work done, in the first 58 minutes and 35 seconds, the bare cell test completed 314 laps, while the batteroo'd train completed its 290 laps. So it didn't even increase the output.Batteroo decreased the RATE of operation, the TIME PERIOD of operation, and the AMOUNT of work done. Fail on every measurable metric.

Err, well, I'm a nerd with a bit of time on my hands just at the moment and not enough sleep; so I used one of those clicker counter things, and just watched the video and clicked it each time the train completed a lap... Cheers though!

Glad you did that, as i was going to ask if anyone does another mechanical test - for them to count the number of operational cycles as part of the result. Also possibly graphed over time, as the sleeved battery appeared to start off with more gusto (although it may have been an illusion of the video size differences)

The sleeve with the broken clips at the plus terminal didn't work anymore, maybe I broke the PCB or something, it is very brittle. But I managed to remove the metal to the minus terminal and the red plastic on top of the PCB:

I measured the caps in place, so could be wrong, but it says 14 uF, for both pairs, so 7 uF each cap (seems to be parallel). The inductor is 2.2 uH, if the in place measurement is right.

The chip has some label, really hard to read it:

Looks like it says "B041" and date code 1629.

And some more train tests: I did close the lid, this should be heavier than the Batteroo sleeve, and tried it again. But I ran out of Energizer batteries, so I used a Duracell. And looks like the bunny ads are true With the Duracell and without the sleeve, it runs for 195 minutes now, instead of 127. But there are different types of the Energizer batteries, maybe this is a type which lasts longer for lower discharge currents.

Then I used a fresh Duracell battery with the Batteroo sleeve, and the train was running for 115 minutes.

Meanwhile the first battery has recovered and I tried it without the Batteroo sleeve. It was running for 7 additional minutes! Of course, this can't be compared because of the longer recovery time and the different battery type, but I guess it will be not much different for the Energizer battery. This means the Batteroo sleeve has no positive effect at all for this train, not even the 3%, because without the sleeve most probably it would have run longer (but maybe a bit slower).

Ok, before I break the second sleeve, too, I'll send it to the next tester, @Ysjoelfir . He might be able to test it with professional EMC and ESD equipment. Was a fun project.

Frank, do you have some digital (or vernier) calipers?If so, can you measure the thickness of the PCB material and the metal.This is just for interest relating to fragility - as your first one clearly didn't last very long.

Thanks for the Youtube video with the toy train Frank. Excellent real world demonstration, shows simply and beyond a doubt that there is no advantage - rather a disadvantage - to using the sleeves compared to a battery by itself. Looking at the train on the round track like a clock, you can even see that the train runs faster throughout the test with just the bare battery. One simple real world test has utterly exposed the Batteroo as total bullshit.

And that's likely going to be very typical, if not pretty universal, for "passive devices" as Batteroo likes to clearly define in their products sheetNow it's onto "Active load" devices like the Mp3 player and any other modern electronic gadget.Batteroo have already admitted on their product sheet that it's not recommended with torches with DC-DC converters, why?, because they are active loads!

That'll be great, I look forward to it! It'd be a pretty simple task for you to put a little magnet on the side of the train and set up a simple reed switch and increasing count-up circuit with a display to show in shot the number of laps completed? That adds a very useful parameter to the tests.

1. If the battery is 1.6V, it looks like the device acts like a forward biased silicon diode with about a 0.8V drop at 100mA. If it was 1v drop at 1A, that would be 1W dissipation which is a lot for that package on a very thin substrate.

You could actually test as the temperature coefficient is about -2.2mV/C. So if you attached 1.6V supply to the input with a 15 ohm resistor, by looking at the increase in output voltage over time, you can measure the die temperature. If the voltage across the resistor rises by 100mV as the chip heats up, you know that there has been a 45 degC temp rise in the die above ambient. The maximum rated temperature will probably be somewhere between 85 degC and 125 degC.

The point is that if a certain current raises the chip to 125degC with a 1.6V battery, that will probably define an absolute maximum current load that the Batteriser can safely be connected to.

2. If the battery is dead (ie replace the battery with a 20A range on a multimeter), what does the Batteriser look like on the output. Is it an open circuit for both positive and negative applied output voltages?Does it look like a diode for a positive applied voltage? Does it look like a diode with a negative applied voltage?In both these cases, if it looks like a diode, what current is going through the battery (the 20A multimeter range)?

The point is that if something uses several batteries, then when the first battery with a batteriser runs flat, the voltage from all the other batteries will be applied to the dead cell/batteriser as a reverse voltage in series with the load.